app/database/db.py

import os
from dotenv import load_dotenv
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

# Ensure environment variables from backend/.env or root .env.local are loaded immediately
BASE_DIR = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
load_dotenv(os.path.join(BASE_DIR, ".env"))
load_dotenv(os.path.join(os.path.dirname(BASE_DIR), ".env.local"))

DATABASE_URL = os.getenv("DATABASE_URL", "")

# Neon requires ssl; SQLAlchemy 2.0 style
engine = create_engine(
    DATABASE_URL or "sqlite:///:memory:",
    pool_pre_ping=True if DATABASE_URL else False,
    pool_size=5 if DATABASE_URL else 1,
    max_overflow=10 if DATABASE_URL else 0,
    connect_args={"sslmode": "require"} if "neon.tech" in DATABASE_URL else {},
)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()


def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()